1. Field of the Invention
The invention relates to a circuit board with a jumper structure, and more particularly, to a circuit board capable of utilizing a combination structure of a microstrip line to co-planar waveguide transition and a co-planar waveguide to microstrip line transition for realizing a signal jumper.
2. Description of the Prior Art
With the rapid progression of technology, the development trend of electronic products is toward thin profile, light weight, and small size. Therefore, circuit design of a printed circuit board is getting complicated. In such a situation, a jumper can be used for avoiding occurrences of signal lines being cross-connected and a mutual interference effect. Please refer to FIG. 1, which is a schematic diagram of a jumper application using an air bridge according to the prior art. As shown in FIG. 1, a first signal S1 is transmitted from an input signal end P1 to a transmission line L1 and further to a transmission line L2 via a metal structure A, so that the first signal S1 can be outputted from an output signal end P2. Similarly, the second signal S2 is transmitted from an input signal end P3 to a transmission line L3 and further outputted from an output signal end P4. As can been seen in FIG. 1, through the metal structure A, the first signal S1 can pass over the transmission line L3 transmitting the second signal S2 with the air bridge method so that mutual interference does not occur between the first signal S1 and the second signal S2. Although using the air bridge method for realizing the jumper provides good isolation, the insertion loss is too great and the return loss is too small. Thus, as the distance between the metal structure A and the transmission line L3 becomes larger, the corresponding characteristics of the insertion loss and the return loss degrade accordingly. Also, when the return loss is too low, mismatch occurs easily in component connections. Therefore, during the manufacturing process, if any mount offset occurs, the related component may require readjustment.
In addition, please refer to FIGS. 2A and 2B, which are respectively a top-view and a bottom-view diagram of a jumper application using a conducting wire according to the prior art. As shown in FIGS. 2A and 2B, a conducting wire ML is used as a jumper for a signal line on a backplane of a substrate. Compared with the above-mentioned air bridge jumper method, the conducting wire jumper method offers better circuit characteristics. However, in the conducting wire jumper method, the conducting wire ML needs to be soldered manually to mount it on the substrate, i.e. the conducting wire ML cannot be mounted through surface mount assembly technology, making assembly time consuming, laborious, and expensive.